JP2015175994A - Antireflection film and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent such an event that a hue of a display screen observed in an oblique direction is recognized as different from a hue of the display screen observed in a frontal direction.SOLUTION: An antireflection film 3 is provided, including at least a linear polarizer 7, a quarter wave plate 6 that gives a retardation corresponding to a quarter wavelength to transmitted light, and a positive C-plate 5. The antireflection film is configured in such a manner that: a leakage light ratio obtained by dividing a luminance at an angle where the leakage light is maximum in a range from 0 degree to 60 degrees of polar angles and from 0 degree to 360 degrees of azimuthal angles, by a frontal luminance, is less than 6.0; and in hues in directions of from 0 degree to 60 degrees of polar angles and from 0 degree to 360 degrees of azimuthal angles, a color difference between a hue at an angle where a difference from a frontal hue is largest and the frontal hue is less than 10.0.

Description

  The present invention relates to an antireflection film using a circularly polarizing plate and an image display device using the antireflection film.

  Conventionally, regarding an image display device, a method has been proposed in which an antireflection film using a circularly polarizing plate is disposed on the panel surface (viewer side surface) of an image display panel, and reflection of extraneous light is reduced by this antireflection film. Here, this antireflection film is composed of a laminate of a linear polarizer and a quarter-wave plate, converts external light directed to the panel surface of the image display panel into linearly-polarized light by the linear polarizer, and continues to the quarter-wave plate. To convert to circularly polarized light. Here, the extraneous light by the circularly polarized light is reflected by the surface of the image display panel or the like, but the rotation direction of the polarization plane is reversed during the reflection. As a result, this reflected light is converted to linearly polarized light in the direction shielded by the linear polarizer by the quarter wavelength plate, contrary to the arrival time, and then shielded by the subsequent linear polarizer, Outgoing emission is significantly suppressed.

  However, since a normal quarter wave plate has positive wavelength dispersion, it has a characteristic that the retardation value increases as the wavelength becomes shorter. For this reason, there was a problem that it functions as a quarter-wave plate only for a specific wavelength and cannot prevent reflection of all incident external light. Therefore, in Patent Document 1 and the like, a ½ wavelength phase difference layer that imparts a phase difference of ½ wavelength to transmitted light, and a ¼ wavelength position that imparts a phase difference of ¼ wavelength to transmitted light. A method has been proposed in which a quarter-wave plate is formed by laminating phase difference layers, and a quarter-wave plate is made to function with a reverse dispersion characteristic by using a material having a positive wavelength dispersion characteristic. In addition, a technique that exhibits reverse dispersion characteristics using a retardation layer made of a liquid crystal material has been proposed (see, for example, Patent Documents 2 and 3). Here, the reverse dispersion characteristic is a wavelength dispersion characteristic in which the phase difference in the transmitted light is smaller toward the shorter wavelength side, and more specifically, retardation at a wavelength of 450 nm (R450) and retardation at a wavelength of 550 nm (R550). Is a wavelength dispersion characteristic where R450 <R550.

  In addition to this, Patent Document 4 discloses a configuration in which a positive C plate is arranged on the image display panel side of a half-wave plate and a quarter-wave plate. According to the configuration disclosed in Patent Document 1, the reflectance in the oblique direction can be brought close to the reflectance in the front direction, and as a result, the visibility in the viewing angle direction can be improved. The C plate is expressed by nx = ny <nz or nx = ny> nz, and the positive C plate is nx = ny <nz, and the in-plane refractive indexes nx and ny are higher than the refractive index nz in the thickness direction. There are small features.

  By the way, in an image display device using this type of antireflection film, there is a problem that when the display screen is viewed from an oblique direction, it is perceived differently from the color when the display screen is viewed from the front direction. Incidentally, in the case of the configuration disclosed in Patent Document 4, although it is possible to improve the color seen from the front direction and the reflectance in the oblique direction, it is difficult to improve the color seen from the oblique direction in this way. is there.

JP-A-10-68816 U.S. Pat. No. 8,119,026 Japanese translation of PCT publication No. 2010-52892 JP 2007-188033 A

  The present invention has been proposed in view of such circumstances, so that the color when viewing the display screen from an oblique direction is not perceived as being different from the case when viewing the display screen from the front direction. The purpose is to do.

  The present inventor has made extensive studies to solve the above-described problems, and as a result, has arrived at the idea of setting the color difference between the front direction and the diagonal direction to be equal to or less than a certain value, thereby completing the present invention. It came.

  Specifically, the present invention provides the following.

(1) In an antireflection film in which at least a linear polarizer, a quarter-wave plate for imparting a phase difference of ¼ wavelength to transmitted light, and a positive C plate are sequentially arranged,
When the polar angle is 0 to 60 degrees and the azimuth angle is 0 to 360 degrees, the ratio of leaked light obtained by dividing the brightness of the angle with the most leaked light by the front brightness is less than 6.0.
In addition, the color difference from the front color at the angle where the difference from the front color is the largest among the colors of the polar angles from 0 to 60 degrees and the azimuth angles from 0 to 360 degrees is smaller than 10.0.

  According to (1), it is possible to prevent the difference in color from being perceived, and it is perceived that the color when viewing the display screen from an oblique direction is different from that when viewing the display screen from the front direction. Can be prevented.

(2) In (1),
The quarter-wave plate is
In-plane retardation Re is 120 nm or more and 160 nm or less,
The positive C plate is
The retardation Rth in the thickness direction is −140 nm or more and −40 nm or less.

  According to (2), with a more specific configuration, it is possible to prevent perception that the color when viewing the display screen from an oblique direction is different from that when viewing the display screen from the front direction.

(3) In (1) or (2),
At least one of the ¼ wavelength plate and the positive C plate was formed of a liquid crystal compound.

  According to (3), with a more specific configuration, it is possible to prevent perception that the color when viewing the display screen from an oblique direction is different from that when viewing the display screen from the front direction.

  (4) An image display in which the antireflection film according to any one of (1), (2), and (3) is arranged on the panel surface of the image display panel by arranging the positive C plate on the panel surface side. apparatus.

  According to (4), the present invention is applied to an image display device so as not to be perceived as having a different color when viewing the display screen from an oblique direction than when viewing the display screen from the front direction. it can.

(5) In (4),
The image display panel is an image display panel made of organic EL or reflective liquid crystal.

  According to (5), regarding an image display device using an image display panel made of organic EL or reflective liquid crystal, the color when viewing the display screen from an oblique direction is different from that when viewing the display screen from the front direction. It can be perceived as being.

  According to the present invention, it is possible to prevent perception that the color when the display screen is viewed from an oblique direction is different from that when the display screen is viewed from the front direction.

It is a figure which shows the image display apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the measurement result of the antireflection film which concerns on the image display apparatus of FIG. It is a figure where it uses for description of a measuring method.

[First Embodiment]
FIG. 1 is a sectional view showing an image display apparatus according to the first embodiment of the present invention. In the image display device 1, the antireflection film 3 is disposed on the panel surface (viewer side surface) of the image display panel 2. Here, various image display panels can be applied to the image display panel 2. However, in this embodiment, although an organic EL image display panel which is a self-luminous image display panel is applied, it may be applied to an image display panel using reflective liquid crystal.

  The antireflection film 3 is a transparent film material 4 that is a positive C plate 5 having an in-plane refractive index smaller than the refractive index in the thickness direction, and a phase difference corresponding to 1/4 wavelength to transmitted light. A four-wave plate 6 and a linear polarizer 7 are sequentially laminated. The antireflection film 3 is arranged on the panel surface of the image display panel 2 by an adhesive layer 8 provided on the base material 4, whereby the image display device 1 is provided with linear polarizers 7, 1/4 from the viewer side. A wave plate 6 and a positive C plate 5 are provided. As a result, the image display device 1 polarizes the extraneous light into linearly polarized light by the linear polarizer 7, converts it to circularly polarized light, and converts it to circularly polarized light by the subsequent quarter wavelength plate. The antireflection film 3 emits the external light by the circularly polarized light to the image display panel 2, and the reflected light by the circularly polarized light whose rotation direction is reversed by the reflection at the image display panel 2 by the quarter wavelength plate 6. The light is converted into linearly polarized light and shielded by the linear polarizer 7, and the reflected light is efficiently suppressed. Further, the positive C plate 5 improves the characteristics in the viewing angle direction.

  In the configuration of FIG. 1, although the antireflection film 3 is shown by the configuration in which the base 4 is sequentially laminated with the positive C plate 5, the quarter wavelength plate 6, and the linear polarizer 7, one side of the base is shown. The quarter wavelength plate 6 and the positive C plate 5 are sequentially laminated, and then the linear polarizer is disposed on the other surface of the substrate. For example, the positive C plate 5, the quarter wavelength plate 6 and the linear polarizer 7 are arranged. In this lamination method, various lamination methods can be applied. Therefore, the base material 4 may be provided between the quarter wave plate 6 and the linear polarizer 7 by this lamination method, for example. For example, when the antireflection film is produced by applying a transfer method, the base material 4 can be omitted. The transfer method refers to, for example, when a desired layer is formed on a base material, the layer is not directly formed on the base material, but can be peeled once on a releasable support. After forming the transfer body by laminating the layers, the layer formed on the support is finally placed on the substrate (transfer base material) on which the layer is to be laminated according to the process, demand, etc. In this method, a desired layer is formed on the substrate by bonding and laminating, and then peeling and removing the support.

  The antireflection film 3 is set so that the ratio of leakage light is smaller than 6.0 and the color difference is smaller than 10.0. Here, the ratio of the leaked light is a value obtained by dividing the maximum value of the amount of leaked light detected at the polar angle of 0 to 60 degrees and the azimuth angle of 0 to 360 degrees by the front luminance. When the ratio of the leaked light is large, the amount of the leaked light in the oblique direction is large, so that the visibility of the display screen when viewed from the oblique direction is lowered. More specifically, the contrast due to the whiteness of the display screen is lowered, and the visibility is lowered.

The color difference is the difference between the color with the largest difference from the color in the front direction and the color in the front direction with respect to the color at the polar angle of 0 to 60 degrees and the azimuth angle of 0 to 360 degrees. * A * b * A difference represented by a distance between chromaticities a * and b * expressed in a color system. More specifically, when the chromaticities a * and b * in the L * a * b * color system of the color with the largest difference are a1 and b1, and the color in the front direction is a2 and b2, ((A1-a2) ² + (b1-b2) ² ) A value represented by ^1/2 . When the color difference is large, it can be said that there is a large difference in color seen from the diagonal direction with respect to the color seen from the front direction, so that the color when viewing the display screen from the diagonal direction is the display screen from the front direction. It becomes easy to perceive when it is different from the case of seeing.

  However, when the ratio of light leakage and the color difference are below a certain value, the color when viewing the display screen from an oblique direction cannot be perceived as being different from when viewing the display screen from the front direction. When either the ratio of leaked light or the color difference becomes a certain value or more, the color when the display screen is viewed from an oblique direction is perceived differently from the case of viewing the display screen from the front direction. Thereby, in this embodiment, by setting the light leakage ratio to be 6.0 or less and the color difference to be 10.0 or less, the color when the display screen is viewed from an oblique direction is It is not perceived as different from the case of viewing the display screen from the direction.

  Furthermore, in this embodiment, the quarter wavelength plate 6 has reverse dispersion wavelength dispersion characteristics, the in-plane retardation Re for light having a wavelength of 550 nm is set to 120 nm or more and 160 nm or less, and the positive C plate 5 has a wavelength of The retardation value Rth in the thickness direction with respect to 550 nm light is set to −140 nm or more and −40 nm or less, so that it is configured to function as a quarter wavelength plate and a positive C plate sufficiently practically.

〔Base material〕
Various transparent film materials and transparent sheet materials can be applied to the substrate 4. In this embodiment, the substrate 4 is a TAC (Triacetylcellulose) film or the like. In the case of the transfer method, the quarter-wave plate and the + C plate may be produced on the PET base material having a large optical anisotropy by finally peeling the base material.

[Positive C plate and 1/4 wavelength plate]
The quarter-wave plate 6 is made of a liquid crystal material having reverse dispersion wavelength characteristics, whereby the image display device 1 is configured to be able to sufficiently suppress reflected light of external light incident from the front in a wide wavelength band. . Further, the normal C plate 5 is made of a liquid crystal material having a reverse dispersion wavelength characteristic similar to that of the quarter wavelength plate 6. The chromatic dispersion characteristics are close to each other, and the above-described leakage light ratio and color difference conditions can be satisfied. In addition, instead of making both the positive C plate 5 and the quarter wavelength plate 6 with a liquid crystal material having reverse dispersion characteristics in this way, the wavelength of reverse dispersion is applied to either one on condition that the above-described conditions are satisfied. A film material according to characteristics may be applied, or one or both of them may be constituted by a liquid crystal material or film material according to positive wavelength dispersion characteristics. In addition, as such a film material, a polystyrene stretched film, an acrylic stretched film, or the like can be applied. The quarter-wave plate 6 is prepared by preparing an alignment film for alignment of a liquid crystal material, applying a coating solution, and then drying and curing. The positive C plate 5 is prepared by applying, drying and curing a coating liquid after a vertical alignment film relating to the positive C plate is prepared.

（ｇは２〜５の整数） As a liquid crystal material applicable to the positive C plate and the quarter wavelength plate, for example, the following liquid crystal compounds can be applied.

(G is an integer of 2 to 5)

  Further, liquid crystal materials include, for example, JP-T-2010-522892, JP-A-2006-243470, JP-A-2007-243470, JP-A-2009-75494, JP-A-2009-62508, JP-A-2009. The liquid crystal compounds having reverse dispersion characteristics described in JP-A No. 179563, JP-A No. 2009-242717, JP-A No. 2009-242718, JP-A No. 4222360, JP-A No. 4186981 can be applied. it can.

〔Comparison result〕
FIG. 2 is a diagram illustrating a comparison result between the example and the comparative example. Examples 1 and 2 are measurement results using the antireflection film according to the above-described embodiment. In this example and comparative example, a quarter-wave plate and the like were produced as follows.

<Preparation of 1/4 wavelength plate A (λ / 4 (A))>
A polyimide alignment agent AL1254 (manufactured by JSR) was spin-coated (2000 rotations / minute, 30 seconds) on a glass substrate, and then dried at 150 ° C. for 1 hour to form a film. The polyimide thin film surface thus formed was rubbed to produce a glass substrate with a horizontal alignment film.
A mixture of compound (1), RM (1), and RM (3) described in JP-T-2010-528992 is dissolved in a 7: 3 mixed solvent of toluene / cyclohexanone at a mixing ratio of 5: 3: 2. As a photopolymerization initiator, Irg184 (Ciba Specialty Chemicals) was added at 5% based on the solid content, and the liquid crystal ink was adjusted so that the solid content concentration was 21.5%.
This liquid crystal ink was applied onto a glass substrate with a horizontal alignment film while adjusting the spin coat rotational speed so that the in-plane retardation Re (550) at a measurement wavelength of 550 nm was 140 nm. Thereafter, the film was dried at a drying temperature of 65 ° C. for 5 minutes, and then fixed by being cured by irradiating with an ultraviolet ray so that the irradiation amount was 380 mJ / cm ² with an H bulb manufactured by Fusion. When chromatic dispersion was evaluated using KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd., a quarter-wave plate A with R450 / R550 = 0.92 was obtained.

<Preparation of 1/4 wavelength plate B (λ / 4 (B))>
A glass substrate with a horizontal alignment film was produced in the same manner as for the quarter-wave plate A.
A liquid crystalline monomer molecule (Paliocolor (registered trademark) LC242 (manufactured by BASF)) having a polymerizable acrylate at both ends and a spacer between the mesogen in the central part and the acrylate was converted into toluene / cyclohexanone 7: 3 was dissolved in a mixed solvent of No. 3, and Irg184 (Ciba Specialty Chemicals) was added as a photopolymerization initiator at 5% based on the solid content, and the liquid crystal ink was adjusted so that the solid content concentration was 21.5%. .
On the glass substrate with a horizontal alignment film, the liquid crystal ink was applied by adjusting the spin coat rotational speed so that the in-plane retardation Re (550) at a measurement wavelength of 550 nm was 140 nm. Then, after drying for 3 minutes at a drying temperature of 90 ° C., it was fixed by curing by irradiation with ultraviolet rays so that the irradiation amount was 380 mJ / cm ² with an H bulb manufactured by Fusion. When wavelength dispersion was evaluated using KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd., a quarter-wave plate B with R450 / R550 = 1.09 was obtained.

<Preparation of 1/2 wavelength plate A (λ / 2 (A))>
A half-wave plate A was produced in the same manner as the quarter-wave plate B, except that the spin coat rotation speed was adjusted so that the in-plane retardation Re (550) at a measurement wavelength of 550 nm was 275 nm. When chromatic dispersion was evaluated using KOBRA-WR manufactured by Oji Scientific Instruments, R450 / R550 = 1.09.

<Preparation of normal C plate A (reverse dispersion (A))>
An alignment film ink prepared by dissolving EXPOA-018, which is one of inorganic vertical alignment films, in an ethanol / butyl cellosolve solvent at a concentration of 4% was spin-coated on a glass substrate (2000 rotations / minute, 30 seconds). Thereafter, the glass substrate was dried at 120 ° C. for 5 minutes to produce a glass substrate with a vertical alignment film.
On the glass substrate with a vertical alignment film, a thickness direction retardation Rth (550) at a measurement wavelength of 550 nm is obtained by using a liquid crystal ink adjusted with a quarter wavelength plate A exhibiting a wavelength dispersion of R450 / R550 = 0.92. Was adjusted to be −70 nm. Then, after drying at a drying temperature of 65 ° C. for 5 minutes, the resin was fixed by irradiating it with ultraviolet rays so as to have an irradiation amount of 380 mJ / cm ² with an H bulb manufactured by Fusion, thereby obtaining a positive C plate A. It was.

<Preparation of Positive C Plate B (Positive Dispersion (B))>
A glass substrate with a vertical alignment film was produced in the same manner as the positive C plate A.
On the glass substrate with a vertical alignment film, a thickness direction retardation Rth (550) at a measurement wavelength of 550 nm is obtained by using a liquid crystal ink adjusted with a quarter wavelength plate B exhibiting a wavelength dispersion of R450 / R550 = 1.09. The coating was carried out by adjusting the spin coat rotation speed so that the thickness of the film became −70 nm. Then, after drying for 3 minutes at a drying temperature of 90 ° C., fixing is performed by irradiating with an ultraviolet ray so as to have an irradiation amount of 380 mJ / cm ² with a H bulb manufactured by Fusion, and fixing to obtain a positive C plate B It was.

<Production of polarizer>
A polyvinyl alcohol film having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30 ° C., and the weight ratio of iodine / potassium iodide / water was 0.02 / It was immersed in a 2/100 aqueous solution at 30 ° C. Then, it was immersed at 56.5 ° C. in an aqueous solution having a potassium iodide / boric acid / water weight ratio of 12/5/100. Subsequently, it was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol. Stretching was mainly performed in the iodine staining and boric acid treatment steps, and the total stretching ratio was 5.3 times.
After bonding and laminating quarter wave plates A, B, etc. to one surface side of the obtained polarizer through a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound, TD80UL-M (manufactured by Fuji Film Co., Ltd.), an isotropic film, is applied to the side opposite to the side where the quarter-wave plate of the polarizer is laminated, and a solvent-free active energy ray containing an alicyclic epoxy compound. It was produced by adhesive bonding through a curable adhesive.
[Comparative Example 1]
Comparative Example 1 has a configuration in which a ¼ wavelength plate is formed of a liquid crystal material having a wavelength characteristic of reverse dispersion, and the normal C plate is omitted. Specifically, the quarter-wave plate A described above was laminated on a polarizer by a transfer method, and then an isotropic film was disposed.

[Example 1]
Example 1 is an example in which a positive C plate is made of a liquid crystal material having a positive wavelength dispersion characteristic, and a quarter wavelength plate is made of a liquid crystal material having a wavelength characteristic of reverse dispersion. Next to the quarter-wave plate A, only the liquid crystal layer is transferred and bonded via a solvent-free active energy ray-curable adhesive containing an alicyclic epoxy compound, and then bonded. A circularly polarizing plate was produced in the same manner as in Comparative Example 1.

[Example 2]
In Example 2, a positive C plate and a quarter-wave plate were made of a liquid crystal material having reverse dispersion wave characteristics. Specifically, in Example 2, only the liquid crystal layer is transferred to the positive C plate A next to the quarter wavelength plate A through a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. Then, a circularly polarizing plate was produced by the same method as in Comparative Example 1.

[Comparative Examples 2 to 4]
In Comparative Examples 2 to 4, the ¼ wavelength plate according to Comparative Example 1 and Examples 1 and 2 is added to the transmitted light for ½ wavelength as disclosed in Japanese Patent Laid-Open No. 10-68816. By laminating a ½ wavelength phase difference layer (λ / 2) for imparting a phase difference and a ¼ wavelength phase difference layer (λ / 4) for imparting a ¼ wavelength phase difference layer to transmitted light. It is the produced structure.

[Comparative Example 2]
Comparative Example 2 uses a quarter-wave plate made of a liquid crystal material having positive wavelength dispersion characteristics and is a laminate of a half-wave retardation layer and a quarter-wave retardation layer, and omits the positive C plate. It is. The absorption axis of the polarizer and the slow axis of the half-wave plate A are connected to one surface side of the polarizer via a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. Only the liquid crystal layer was transferred and bonded so that the angle formed was 15 degrees. Furthermore, the angle formed between the absorption axis of the polarizer and the slow axis of the quarter-wave plate B is 75 degrees through a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. Thus, a circularly polarizing plate according to Comparative Example 2 was produced in the same manner as in Comparative Example 1 except that only the liquid crystal layer was transferred and bonded.

[Comparative Example 3]
As in Comparative Example 2, Comparative Example 3 uses a quarter-wave plate made of a liquid crystal material having a positive wavelength dispersion characteristic, which is a laminate of a half-wave retardation layer and a quarter-wave retardation layer, As in Example 1, this is an example in which a positive C plate is made of a liquid crystal material having a positive wavelength dispersion characteristic.

  The absorption axis of the polarizer and the slow axis of the half-wave plate A are connected to one surface side of the polarizer via a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. Only the liquid crystal layer was transferred and bonded so that the angle formed was 15 degrees. Furthermore, the angle formed between the absorption axis of the polarizer and the slow axis of the quarter-wave plate B is 75 degrees through a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. Thus, only the liquid crystal layer was transferred and bonded. Further, in the same manner as in Comparative Example 1 except that only the liquid crystal layer was transferred and bonded to the positive C plate B via a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. A circularly polarizing plate according to Comparative Example 2 was produced.

[Comparative Example 4]
Comparative Example 4 uses a quarter-wave plate made of a liquid crystal material having a positive wavelength dispersion characteristic, which is a laminate of a half-wave retardation layer and a quarter-wave retardation layer, as in Comparative Example 2. Similarly to Example 2, this is an example in which a normal C plate is made of a liquid crystal material having reverse wavelength dispersion characteristics.

The absorption axis of the polarizer and the slow axis of the half-wave plate A are connected to one surface side of the polarizer via a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. Only the liquid crystal layer was transferred and bonded so that the angle formed was 15 degrees. Furthermore, the angle formed between the absorption axis of the polarizer and the slow axis of the quarter-wave plate B is 75 degrees through a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. Thus, only the liquid crystal layer was transferred and bonded. Further, in the same manner as in Comparative Example 1 except that only the liquid crystal layer was transferred and adhesively bonded to the positive C plate A via a solventless active energy ray-curable adhesive containing an alicyclic epoxy compound. A circularly polarizing plate according to Comparative Example 3 was produced.

<Evaluation>
In order to evaluate the light leakage ratio and the color difference, a pressure-sensitive adhesive (P-3132, Lintec Co., Ltd.) is provided on the side opposite to the isotropic film of the circularly polarizing plate produced in Examples and Comparative Examples as shown in FIG. An aluminum vapor-deposited film (Metallic 125KT2 manufactured by Panac Co., Ltd.) was installed through the product, and the reflection chromaticity and reflection luminance were measured with a measuring instrument (EZ Contrast manufactured by ELDIM), and the light leakage ratio and the color difference were calculated.

Moreover, it observed by 10 persons in the room | chamber interior of peripheral illuminance 400 lux (light place), and evaluated visually according to the following reference | standard. Note that the visual evaluation of FIG. 2 uses the largest number of evaluations as observation results. Here, the double circle is a case where the color difference is small and perceived as good, and the color difference was <8.0.
In addition, ◯ indicates a case where it is judged that there is a little color difference but there is no problem in practical use, and the color difference was <10.0. Further, x indicates a case where there is a color difference and it is determined that there is a problem in actual use, and the color difference was ≧ 10.0.

  In these examples and comparative examples, the leakage light ratio (leakage light ratio) and the color difference increase as the polar angle increases, and as a result, the color of the display screen changes more as viewed from a tilted direction. It turns out that it is big. In particular, in Comparative Examples 1 to 4, when the polar angle is 40, the color difference is already greater than 10.0, thereby changing the color tone when viewed from an oblique direction relative to when viewed from the front direction. It turns out that it is perceived. In Comparative Examples 2 to 4, the ratio of leakage light is greatly increased, so that the display screen is recognized as white when viewed from an oblique direction, and as a result, the visibility is reduced. It will be.

  However, in the first and second embodiments, even when the polar angle is 60 degrees, the leakage light ratio is held to be smaller than 6.0 and the color difference is smaller than 10.0. It can be perceived that the color when viewing the screen is different from that when viewing the display screen from the front.

Other Embodiment
As mentioned above, although the specific structure suitable for implementation of this invention was explained in full detail, this invention can change the structure of the above-mentioned embodiment variously in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 Image display panel 3 Antireflection film 4 Base material 5 Positive C plate 6 1/4 wavelength plate 7 Linear polarizer 8 Adhesive layer

Claims (5)

In an antireflection film in which a linear polarizer, a quarter wavelength plate that imparts a phase difference of ¼ wavelength to transmitted light, and a positive C plate are arranged,
When the polar angle is 0 to 60 degrees and the azimuth angle is 0 to 360 degrees, the ratio of leaked light obtained by dividing the brightness of the angle with the most leaked light by the front brightness is less than 6.0.
In addition, the color difference from the front color at the angle where the difference from the front color is the largest among the colors of the polar angle from 0 to 60 degrees and the azimuth angle from 0 to 360 degrees is less than 10.0. the film. The quarter-wave plate is
In-plane retardation Re is 120 nm or more and 160 nm or less,
The positive C plate is
The antireflection film according to claim 1, wherein retardation Rth in the thickness direction is −140 nm or more and −40 nm or less. The antireflection film according to claim 1, wherein at least one of the ¼ wavelength plate and the positive C plate is formed of a liquid crystal compound. An image display device, wherein the antireflection film according to any one of claims 1, 2, and 3 is arranged on a panel surface of an image display panel by arranging the positive C plate on the panel surface side. The image display device according to claim 4, wherein the image display panel is an image display panel using organic EL or reflective liquid crystal.

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